Lac genes are most effectively expressed in presence of Lactose and its analogs when glucose is absent.
Explanation:
A unit of prokaryotic gene expression and regulation,which includes structural genes and regulatory sequences recognized by regulatory gene product is called operon.
<em>Lac </em>structural genes are a part of<em> Lac</em> operon. The <em>Lac </em>operon consists of three, structural genes,an operator and a promoter.The product of Lac operon is involved in the conversion of disaccharide lactose into glucose and Galactose.
Lactose and its analogs are inducers of<em> Lac </em>operon. So, the structural genes are best expressed in presence of Lactose. Glucose and galactose are repressors of lac gene so the genes are repressed in presence of glucose.
When a doctor refuses to care for a certain patient. This can be for numerous reasons, maybe they are not fit to undergo a surgery of some sort, or are being problematic. Either or the doctor nor the patient benefit form this. Doctor misses out on someone to help (i assume that’s the attitude of one working for the greater good) and the patient misses the opportunity to possibly get the help they need.
D. Cannot repopulate the world with endangered organism